i currently have about 700 miles of experience running a 10% mix of WMO, and so far so good. after all i've read, you don't want to try to run it straight, as its just way too thick, but a conservative mix appears to be pretty safe.
as was mentioned by several guys in my thread, filtering it is an important step. so far i've poured a total of 5.5 gallons into my tank, all filtered through a 100 micron paint filter. i plan to start using a blue-jean filter before my next fill-up, which is reportedly in the 5-10 micron range.
for running this mix, my MPG has gone from about 14.5 to 16, when only counting the diesel fuel and not the oil i added. an increase of 1.5 points puts a smile on my face!
Linus was mixing the two, and it did get him into some serious issues with sludge coming out of the fuel and clogging up filters and stuff. but since his test was with a combination of WMO and WVO, i don't think the problems he had will apply to those of us who are only playing with WMO and #2